Fatigue

Fatigue is a process (succession of mechanisms) which, under the action of stresses or deformations that vary over time, modifies the local properties of a material. The latter can lead to the formation of cracks and possibly the rupture of the structure.

Fatigue is characterized by a range of stress variations that can be well below the yield strength of the material.

The main steps in fatigue failure of a joint are crack initiation (if defects are not already present in the material), crack propagation and final failure.